You won’ Adam n’ Eve this. Sent the initial text/email. (Advising him that LBA on its way) His response was “I’m not a business, but a sole trader”!!!
That makes little difference, you send and address the LBA to what ever name he used to represent himself as a trader, but also include his name. You still send him the LBA, but usual is to say you will allow him 7 or 14 days to respond to it, with a response from him in writing.
Failing a satisfactory response from him, you go on the Small Claims website, fill the form in claiming the amount he owes you, plus any reasonable additional direct costs you have incurred and briefly what happened and pay the fee. Once that is done he owes you the entire cost of the claim, plus the fees, if he wants to settle at that point. If it gets as far as going into court, if he fails to appear to defend it, you win. If you fail to appear, he might win.